Between
the shaft rotates with zero torque, thus there will be no
acceleration
ω
2
=
ω
3
.
Between
, a constant output torque
is applied causing the flywheel to slow
down from
ω
3
to
ω
4
.

Shigley’s Mechanical Engineering Design,
9
th
Ed.
Class Notes by:
Dr. Ala Hijazi
Ch.16
Page 12 of 13
The work input to the flywheel is:
And the work output is:
- If
then
.
- If
then
.
- If
then
The work done on the flywheel between
can also be found as the difference in
kinetic energy
.
Most of the torque-angular position functions encountered in engineering application
are so complicated and they require using numerical integration to find the total work
(
area under the curve
).
Fig 18-28
shows the torque of a one cylinder engine for one cycle.
Integrating the curve gives the total energy supplied by the engine. Then dividing
the result by the length of one-cycle
(
4π
) gives the mean torque
value
of the
engine.
The allowable range of speed fluctuation
is usually defined using the
“
Coefficient of speed
fluctuation
”
:
where
ω
is the nominal
angular velocity:
Substitute
in the energy difference equation we get:
where
is the area under the torque curve
This equation can be used to obtain the flywheel inertia “
” needed to satisfy the
required
value.

Shigley’s Mechanical Engineering Design,
9
th
Ed.
Class Notes by:
Dr. Ala Hijazi
Ch.16
Page 13 of 13
See
Example 16-6
from text

#### You've reached the end of your free preview.

Want to read all 13 pages?